Please tell me that, after noticing that the best interval length is 2, you simplified your implementation to something like this def perform_union_dnc(pat

Please tell me that, after noticing that the best interval length is 2, you simplified your implementation to something like this def perform_union_dnc(paths): if len(paths) == 0: return None if len(paths) == 1: return paths[0] middle = len(paths) // 2 left = perform_union_dnc(paths[:middle]) right = perform_union_dnc(paths[middle:]) return perform_union_naive([left, right]) It's not exactly the same algorithm (top-down merging instead of bottom-up) but the performance should be very close. Also, it can be optimized to avoid temporary lists if that turns out to be a win.